BlUTISII ISLES AND THEIR MIGRATORY RIRDS 37 



appear on our shores in spring and the last to depart 

 from them in the autumn. That this should be so is 

 readily explained by the fact that the summer homes of 

 most of them lie in the northern lands, where the nesting 

 period is naturally much later than in our own country. 



The White and Grey-headed Wagtails, Blue- 

 throated Warbler, Honey Buzzard, Little Stint, and 

 Curlew Sandpiper are examples of these transitory 

 migrants. 



Before dismissing the birds of passage, it must be 

 made clear that in addition to the species which occur 

 with us only as such, vast numbers of individuals belong- 

 ing to almost all the species which are summer^ and 

 winter visitors to our islands occur also on passage on 

 our shores. Thus many Swallows summer up to a high 

 latitude in Scandinavia, and many Fieldfares winter in 

 Southern Europe, and both these species traverse the 

 British coastlines to get to their respective destinations. 



The various migrations performed by these summer 

 visitors, winter visitors, birds of passage, and partial 

 migrants are phases of two seasonal movements only — 

 all the birds are proceeding to summer haunts in spring, 

 all to winter retreats in autumn. 



In the Local Movements we see migration in its 

 simplest aspect, in the Birds of Passage in the highest 

 stage of its development. 



Winter Movements. — In addition to the regtilar 

 migrations above described, there are cold-weather 

 movements due to, and dependent upon, the climatic 



' The following summer visitors to the British Isles do Jtot occur with us 

 as birds of passage to and from the north : — Nightingale, Marsh Warbler, 

 Stone-Curlew, and Kentish Plover. The Red-backed Shrike, Lesser 

 Whitethroat, Wryneck, and Ruff, which occur on passage in Scotland, are 

 not summer visitors to Northern Britain. 



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